1. Field of the Invention
The present invention relates to an aluminum matrix composite, and a method for making same, wherein the term "aluminum" includes aluminum alloy. More particularly, the present invention relates to an aluminum matrix composite containing evenly dispersed reinforcement particles, and a method for making same.
2. Description of the Prior Art
To enable metal matrix composites to exhibit their characteristics the matrix preferably contains evenly dispersed reinforcement particles.
Recently the mechanical alloying method has become known in the field, which is designed to secure an even dispersion of reinforcement particles. According to the known mechanical alloying method a primary powdery composite is produced in which the reinforcement particles are strongly bonded to the matrix, and then the primary powdery composite is metallurgically processed into a secondary powdery composite. The mechanical alloying methods are already known in the art; for example, Japanese Patent Publication (unexamined) Nos. 60-131943, 60-1319 and 60-9837 disclose them.
However the matrix composites produced under the conventional metallurgical methods are less ductile and fragile. To use them for practical purposes a further process is required to increase the tenacity and heat-proofness.
The inventor has found out through study and researches that the insufficient tenacity is due to the presence of excessive amounts of oxygen and carbon which is unavoidably brought about during the mechanical alloying process. The oxygen and carbon shorten the average inter-particle distance to increase a restraint against dislocation, which makes the matrix composites less tenacious, and fragile.